with my 1999 Ford towing pkg, I am wondering if it is already wired for a brake controller and all I would have to do is mount it under the dash and plug it in.  Nothing is ever that easy...  is it?

If the truck came with the brake controler pigtail...or you ordered one with your controler it is that easy!

I don't know about fords, but my 02 and 03 dodges had plugs.  I had to order the right one to go with my controler form toshiba.  I didn't know about it when I had the 02 done, the installer spliced into the wiring, but with the 02 I insisted that they used the plug instead of cutting wires.    That sounds backwards I know, but I got a 03 1500 and then traded it in this year for a 02 2500.

Look up under your dash (right in front of your knees) for a flat/square plug. 

If You bought the truck new it should have it in the glove box.